U.S. patent application number 14/413430 was filed with the patent office on 2015-06-18 for system and method for controlling operation of a metal-air battery.
The applicant listed for this patent is PHINERGY LTD.. Invention is credited to Avraham Yadgar.
Application Number | 20150171495 14/413430 |
Document ID | / |
Family ID | 49915487 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150171495 |
Kind Code |
A1 |
Yadgar; Avraham |
June 18, 2015 |
SYSTEM AND METHOD FOR CONTROLLING OPERATION OF A METAL-AIR
BATTERY
Abstract
A system and method for controlling operation a metal-air
battery are provided. A system and method for controlling operation
a metal-air battery may include controlling a current drawn from
the battery; and controlling a temperature of the battery. A system
and method may draw a preconfigured amount of power from a
metal-air battery, and draw power from a rechargeable device when
power required is greater than the preconfigured power.
Inventors: |
Yadgar; Avraham; (Kiryat
Ono, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PHINERGY LTD. |
LOD |
|
IL |
|
|
Family ID: |
49915487 |
Appl. No.: |
14/413430 |
Filed: |
July 9, 2013 |
PCT Filed: |
July 9, 2013 |
PCT NO: |
PCT/IL13/50583 |
371 Date: |
January 8, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61669160 |
Jul 9, 2012 |
|
|
|
Current U.S.
Class: |
429/403 |
Current CPC
Class: |
H01M 4/38 20130101; H01M
10/486 20130101; H01M 10/613 20150401; H01M 12/08 20130101; H01M
12/06 20130101; H01M 10/615 20150401; H01M 10/625 20150401; H01M
10/6567 20150401; H01M 10/443 20130101; H01M 2220/20 20130101; Y02E
60/10 20130101; H01M 10/48 20130101; H01M 10/635 20150401; Y02T
10/70 20130101; H01M 10/484 20130101 |
International
Class: |
H01M 12/08 20060101
H01M012/08 |
Claims
1. A method of controlling operation of a metal-air battery, the
method comprising: controlling a current drawn from the battery;
and controlling a temperature of the battery.
2. The method of claim 1, further comprising causing the battery to
operate according to a profile, the profile defining at least one
of: an energetic utilization ratio, power, an electrolyte
utilization value and a corrosion rate.
3. (canceled)
4. The method of claim 1, further comprising repeatedly setting the
current drawn from the battery and the temperature of the battery
until a desired energetic utilization ratio is achieved.
5. The method of claim 1, further comprising determining an age of
an electrolyte included in the battery and controlling, based on
the age of the electrolyte, at least one of: an electric current
provided by the battery, a temperature of the battery, a
temperature of the electrolyte and voltage provided by the
battery.
6. The method of claim 1, further comprising controlling at least
one of: an electric current provided by the battery, a temperature
of the battery, a temperature of an electrolyte and a voltage
provided by the battery, such that a predefined ratio between an
amount of metal consumed in an electrochemical reaction and a total
amount of metal in the battery is maintained.
7. The method of claim 1, further comprising controlling at least
one of: an electric current provided by the battery, a temperature
of the battery, a temperature of the an electrolyte and a voltage
provided by the battery such that a predefined corrosion rate of
metal included in the battery is maintained.
8. The method of claim 1, further comprising controlling at least
one of: an electric current provided by the battery, a temperature
of the battery, a temperature of an electrolyte and a voltage
provided by the battery to maximize an amount of energy drawn from
the battery per volume unit of electrolyte included in the
battery.
9. The method of claim 1, further comprising controlling at least
one of: an electric current provided by the battery, a temperature
of the battery, a temperature of an electrolyte and a voltage
provided by the battery to minimize a rate by which metal is
dissolved in electrolyte included in the battery.
10. (canceled)
11. The method of claim 1, wherein controlling a temperature of the
battery includes controlling a circulation of electrolyte included
in the battery.
12. The method of claim 1, comprising: prior to activating the
battery, determining an age of an electrolyte included in the
battery; and setting the temperature of the electrolyte according
to a profile.
13. A system comprising: a metal-air battery; and a controller, the
controller configured to: control a current drawn from the battery,
and control a temperature of the battery.
14. The system of claim 13, comprising a rechargeable device, the
system configured to: draw a predefined power from the metal-air
battery, the predefined power defined according to an average power
requirement; and draw power from the rechargeable device when power
required by the electric car is greater than the predefined
power.
15. The system of claim 13, wherein the controller is configured to
cause the battery to operate according to a profile, the profile
defining at least one of: an energetic utilization ratio, power, an
electrolyte utilization value and a corrosion rate.
16. (canceled)
17. The system of claim 13, wherein the controller is configured to
repeatedly set the current drawn from the battery and the
temperature of the battery until a desired energetic utilization
ratio is achieved.
18. (canceled)
19. The system of claim 13, wherein the controller is configured to
control at least one of: an electric current provided by the
battery, a temperature of the battery, a temperature of an
electrolyte and a voltage provided by the battery such that a
predefined ratio between an amount of metal consumed in an
electrochemical reaction and a total amount of metal in the battery
is maintained.
20. The system of claim 13, wherein the controller is configured to
control at least one of: an electric current provided by the
battery, a temperature of the battery, a temperature of an
electrolyte and a voltage provided by the battery such that a
predefined corrosion rate of metal included in the battery is
maintained.
21. The system of claim 13, wherein the controller is configured to
control at least one of: an electric current provided by the
battery, a temperature of the battery, a temperature of an
electrolyte and a voltage provided by the battery to maximize an
amount of energy drawn from the battery per volume unit of
electrolyte included in the battery.
22.-24. (canceled)
25. The system of claim 13, wherein the controller is configured
to: prior to activating the battery, determine an age of an
electrolyte included in the battery; and set the temperature of the
electrolyte according to a profile.
26. A an electric vehicle comprising: a metal-air battery;
rechargeable device; and a controller, the controller configured to
set the power supplied to the electric vehicle according to a
profile, the profile defining at least one of: an energetic
utilization ratio, a power rate, an electrolyte utilization value,
and a corrosion rate.
27. (canceled)
28. The electric vehicle of claim 26, wherein when power required
by the electric vehicle is less than a preconfigured power, the
electric vehicle is configured to use power provided by the
metal-air battery to charge the rechargeable device.
29. The electric vehicle of claim 26, wherein the capacity of the
rechargeable device is designed to supply an average daily energy
consumption of the electric vehicle and wherein the metal-air
battery is designed to supply energy in excess of the average daily
energy
Description
FIELD OF THE INVENTION
[0001] The present invention pertains to batteries. In particular,
the present invention pertains to controlling an operation of a
metal-air battery.
BACKGROUND OF THE INVENTION
[0002] As known in the art, a battery is a component that stores
chemical energy and makes the energy available in an electrical
form. Metal-air batteries use oxidation of metal with oxygen from
air to produce electricity. Electric energy produced by batteries
is used by various systems and components, e.g., consumer products,
industrial systems ant the like. However, known systems and methods
draw energy from a battery as, and when needed. Accordingly,
utilization of energy stored in a battery may not be optimal.
SUMMARY OF THE INVENTION
[0003] A method may include controlling a current drawn from a
metal-air battery; and controlling a temperature of the battery. A
method may include causing the battery to operate according to a
profile, the profile defining at least one of: an energetic
utilization ratio, power, an electrolyte utilization value and a
corrosion rate. In an embodiment, the profile is automatically
selected by a controller.
[0004] A method may include repeatedly setting the current drawn
from a battery and setting the temperature of the battery until a
desired energetic utilization ratio is achieved. A method may
include determining an age of an electrolyte included in the
battery and controlling, based on the age of the electrolyte, at
least one of: an electric current provided by the battery, a
temperature of the battery, a temperature of the electrolyte and
voltage provided by the battery. A method may include controlling
at least one of: an electric current provided by the battery, a
temperature of the battery, a temperature of the electrolyte and a
voltage provided by the battery, such that a predefined ratio
between an amount of metal consumed in an electrochemical reaction
and a total amount of metal in the battery is maintained.
[0005] A method may include controlling at least one of: an
electric current provided by the battery, a temperature of the
battery, a temperature of the electrolyte and a voltage provided by
the battery such that a predefined corrosion rate of metal included
in the battery is maintained. A method may include controlling at
least one of: an electric current provided by the battery, a
temperature of the battery, a temperature of the electrolyte and a
voltage provided by the battery to maximize an amount of energy
drawn from the battery per volume unit of electrolyte included in
the battery. A method may include controlling at least one of: an
electric current provided by the battery, a temperature of the
battery, a temperature of the electrolyte and a voltage provided by
the battery to minimize a rate by which metal is dissolved in
electrolyte included in the battery.
[0006] A method may include controlling a temperature of the
battery by controlling a temperature and circulation of electrolyte
included in the battery. A method may include, prior to activating
a battery, determining an age of an electrolyte included in the
battery; and setting the temperature of the electrolyte according
to a profile.
[0007] A system may comprise a metal-air battery; and a controller,
the controller configured to: control a current drawn from the
battery, and control a temperature of the battery. A system may
comprise a rechargeable device and the system may be configured to:
draw a predefined power from the metal-air battery, the predefined
power defined according to an average power requirement; and draw
power from the rechargeable device when power required by the
electric car is greater than the predefined power.
[0008] A controller included in a system may be configured to cause
a battery to operate according to a profile, the profile defining
at least one of: an energetic utilization ratio, power, an
electrolyte utilization value and a corrosion rate. A controller
included in a system may be configured to automatically select a
profile and cause a battery to operate according to a selected
profile. A controller included in a system may be configured to
repeatedly set the current drawn from the battery and the
temperature of the battery until a desired energetic utilization
ratio for the battery is achieved.
[0009] A controller included in a system may be configured to
determine an age of an electrolyte included in the battery and to
control, based on the age of the electrolyte, at least one of: an
electric current provided by the battery, a temperature of the
battery, a temperature of the electrolyte and voltage provided by
the battery. A controller included in a system may be configured to
control at least one of: an electric current provided by the
battery, a temperature of the battery, a temperature of the
electrolyte and a voltage provided by the battery such that a
predefined ratio between an amount of metal consumed in an
electrochemical reaction and a total amount of metal in the battery
is maintained. A controller included in a system may be configured
to control at least one of: an electric current provided by the
battery, a temperature of the battery, a temperature of the
electrolyte and a voltage provided by the battery such that a
predefined corrosion rate of metal included in the battery is
maintained.
[0010] A controller included in a system may be configured to
control at least one of: an electric current provided by the
battery, a temperature of the battery, a temperature of the
electrolyte and a voltage provided by the battery to maximize an
amount of energy drawn from the battery per volume unit of
electrolyte included in the battery. A controller included in a
system may be configured to control at least one of: an electric
current provided by the battery, a temperature of the battery, a
temperature of the electrolyte and a voltage provided by the
battery to minimize a rate by which metal is dissolved in
electrolyte included in the battery. A system may include a battery
that comprises metal anodes made of one of: Aluminum, Zinc and
Iron.
[0011] A system may control a temperature of a battery by
controlling a temperature and circulation of electrolyte included
in the battery. A controller included in a system may be configured
to, prior to activating the battery, determining an age of an
electrolyte included in the battery; and setting the temperature of
the electrolyte according to a profile. A an electric vehicle
according to an embodiment may comprise a metal-air battery;
rechargeable device; and a controller, the controller configured to
set the power supplied to the electric vehicle according to a
profile, the profile defining at least one of: an energetic
utilization ratio, a power rate, an electrolyte utilization value,
and a corrosion rate.
[0012] An electric vehicle according to an embodiment may be
configured to consume a preconfigured power from the metal-air
battery; and consume power from the rechargeable device when power
required by the electric vehicle is greater than the preconfigured
power. According to an embodiment, when power required by the
electric vehicle is less than a preconfigured power, the electric
vehicle may be configured to use power provided by a metal-air
battery to charge a rechargeable device. According to an
embodiment, a capacity of the rechargeable device may be designed
to supply an average daily energy consumption of an electric
vehicle and a metal-air battery may be designed to supply energy in
excess of the average daily energy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The subject matter regarded as the invention is particularly
pointed out and distinctly claimed in the concluding portion of the
specification. The invention, however, both as to organization and
method of operation, together with objects, features and advantages
thereof, may best be understood by reference to the following
detailed description when read with the accompanied drawings in
which:
[0014] FIG. 1 shows parameters that effect operation of a metal-air
cell;
[0015] FIG. 2 shows an exemplary system according to embodiments of
the invention;
[0016] FIG. 3 shows an exemplary system according to embodiments of
the invention;
[0017] FIG. 4 shows an exemplary system configuration according to
embodiments of the invention;
[0018] FIG. 5 shows an exemplary flow according to embodiments of
the invention; and
[0019] FIGS. 6A and 6B illustrate a behavior of a temperature
controlled metal-air battery according to embodiments of the
invention.
[0020] It will be appreciated that for simplicity and clarity of
illustration, elements shown in the figures have not necessarily
been drawn to scale. For example, the dimensions of some of the
elements may be exaggerated relative to other elements for clarity.
Further, where considered appropriate, reference numerals may be
repeated among the figures to indicate corresponding or analogous
elements.
DETAILED DESCRIPTION OF THE INVENTION
[0021] In the following detailed description, numerous specific
details are set forth in order to provide a thorough understanding
of the invention. However, it will be understood by those having
ordinary skill in the art that the invention may be practiced
without these specific details. In other instances, well-known
methods, procedures, components, modules, units and/or circuits
have not been described in detail so as not to obscure the
invention.
[0022] Although embodiments of the invention are not limited in
this regard, the terms "plurality" and "a plurality" as used herein
may include, for example, "multiple" or "two or more". The terms
"plurality" or "a plurality" may be used throughout the
specification to describe two or more components, devices,
elements, units, parameters, or the like.
[0023] Unless explicitly stated, the method embodiments described
herein are not constrained to a particular order or sequence.
Additionally, some of the described method embodiments or elements
thereof can occur or be performed at the same point in time or
overlapping points in time. As known in the art, an execution of an
executable code segment such as a function, task, sub-task or
program may be referred to as execution of the function, program or
other component.
[0024] Although embodiments of the invention are not limited in
this regard, discussions utilizing terms such as, for example,
"processing," "computing," "calculating," "determining,"
"establishing", "analyzing", "checking", or the like, may refer to
operation(s) and/or process(es) of a computer, a computing
platform, a computing system, or other electronic computing device,
that manipulate and/or transform data represented as physical
(e.g., electronic) quantities within the computer's registers
and/or memories into other data similarly represented as physical
quantities within the computer's registers and/or memories or other
information storage medium that may store instructions to perform
operations and/or processes.
[0025] Embodiments of the invention may enable controlling
operation of a metal-air cell or battery (e.g., an aluminum-air
battery) in order to improve its utilization. Although for the sake
of simplicity, aluminum-air cell or battery is mainly referred to
herein, it will be understood that other metal-air cells or
batteries may be applicable. For example, systems and methods
according to embodiments of the invention may use Zinc-air or any
other suitable metal-air batteries or cells.
[0026] An aluminum-air battery consumes aluminum in order to
generate electric energy. The electrochemical reaction that takes
place in an aluminum-air cell is as shown by equation (1)
below:
4Al+6H.sub.2O+3O.sub.24Al(OH).sub.3+2.71v (1)
[0027] In practice, an aluminum-air cell may operate at a voltage
lower than 2.7v as shown by equation (1), typically 0.7 to 1.5
volts. The rest of the energy is released as heat. In addition to
this reaction, which results in electric energy, the a corrosion
reaction may take place as shown by equation (2) below:
2Al+6H.sub.2O2Al(OH).sub.3+3H.sub.2 (2)
[0028] The reaction shown by equation (2) consumes aluminum but
does not release electrical energy. Therefore, it is considered an
unwanted or parasitic reaction. An additional side effect of the
reaction shown by equation (2) is the release of Hydrogen.
[0029] As referred to herein, the term "columbic efficiency" of a
metal-air cell or metal-air battery is the ratio between the amount
of metal that is consumed in the electrochemical reaction (1) and
the total amount of metal that is consumed, that is, the amount of
metal that is consumed according to both equation (1) and (2).
[0030] The specific energy of aluminum is known in the art to be
8.1 kWh/kg. As referred to herein, the term "energetic utilization"
of aluminum is the ratio between the amount of electric energy that
is extracted from one ("1") kilogram (Kg) of aluminum, and the
total energy included in one ("1") Kg of aluminum.
[0031] Generally, as referred to herein, the term "energetic
utilization" of metal is determined by two factors:
[0032] 1. The corrosion rate--which determines, or effects,
columbic efficiency. That is, how much metal is lost without
producing electric energy, and
[0033] 2. Actual cell voltage--which is related to the part or
portion of the electric energy that is exploited (e.g., not
released as heat).
[0034] As referred to herein and known in the art, an electrolyte
(or electrolyte solution) may be any liquid that contains ions and
can be decomposed by electrolysis. An electrolyte may include any
matter, substance or compound that ionizes when dissolved in
suitable ionizing liquid or solvent, e.g., water. In an
aluminum-air cell or battery, where alkaline electrolyte such as
KOH or NaOH is used, an additional reaction takes place as shown by
equation (3):
Al(OH).sub.3+KOHKAl(OH).sub.4 (3)
[0035] The product of the reaction shown by equation (3) is
dissolved in the electrolyte throughout the operation of the
battery, and typically causes the voltage of the cells to gradually
decrease, down to some low voltage threshold (typically 0.7-0.9
volt).
[0036] As referred to herein, the term "electrolyte utilization" is
the amount of energy that can be drawn from a metal-air cell before
it reaches the low voltage threshold (e.g., the range of 0.7-0.9
volt).
[0037] Electrolyte utilization may be affected by the corrosion
rate and by cells voltage. The term "corrosion rate" as referred to
herein is the rate or measure by which metal is dissolved in the
electrolyte without contributing electric energy. The term "cell
voltage" as referred to herein generally relates to the electrical
potential difference between anode and cathode of cell in a
battery. Therefore, cell voltage may be indicative of the amount of
energy that can be extracted from the useful metal in a metal-air
cell.
[0038] As referred to herein, the specific energy of a metal-air
battery is the amount of energy that can be extracted from the
battery, divided by the battery's total weight. As described
herein, an embodiment may improve or raise the specific energy of a
metal-air battery by improving the utilization of the metal fuel
and/or by improving the utilization of the electrolyte. It will be
noted that an improvement of the utilization of an electrolyte in a
battery is enabled by embodiments of the invention even though the
electrolyte itself does not release energy but rather, enables the
metal (e.g., aluminum) in a metal-air battery to release energy as
described.
[0039] An embodiment of the invention increases the energetic
efficiency of a metal-air battery by controlling operational
parameters of the cells in the battery, such as discharge current
and battery temperature. An embodiment of the invention increases
the energetic efficiency of a metal-air battery by controlling a
rate at which electrolyte is circulated through the battery. For
example and as described, a pump controlled by a controller may
circulate an electrolyte through chambers or cells in a battery at
a controlled rate or according to controlled intervals. A
controller may control a pump and valves such that electrolyte
flows through specific spaces or chambers in a battery. In one
embodiment, by controlling electrolyte temperature the system
controls the temperature of a battery. In one embodiment, by
controlling flow rate of electrolyte in a battery and/or
controlling a heat exchanger, a system controls the temperature of
a battery and thereby controls a voltage of the battery.
[0040] Generally, the performance of a metal-air cell or battery is
determined by various parameters such as cathode composition and
structure, anode composition and structure, electrolyte
composition, working temperature, electrolyte flow rate, air flow
rate, discharge profile, etc. While some of the parameters such as
physical structure and composition of elements, e.g., cell or
battery structure and cathode composition, are determined by the
cell or battery design and/or manufacturer, other parameters, such
as working temperature, drawn current, voltage and a discharge
profile, may be measured and set by an embodiment of the invention.
It will be understood that various designs or battery types may be
used according to embodiments of the invention and that embodiments
of the invention may be applicable to any suitable battery. For
example, batteries of various sizes, number of cells and the like
may be applicable and used without departing from the scope of the
present invention.
[0041] An embodiment of the invention may compensate for, or take
into account, design parameters and/or evolution of a battery's
construction or composition. For example, the distance between the
anode and the cathode is changing throughout the operation of a
metal-air cell or battery. As the anode is consumed, the distance
between its surface and the cathode increases. Such and other
changing parameters determine the cell's or battery's effective
voltage and effect the corrosion rate during operation, as well as
effecting electrolyte utilization. These parameters, in turn,
determine the energetic utilization of the cell or battery. An
embodiment may adjust working parameters (e.g., temperature of, or
power consumption from a battery) based on changing or evolving
parameters. For example, a system compensates for a decrease in
voltage produced by a metal-air battery (e.g., a decrease resulting
from corrosion) by increasing the temperature of the battery.
[0042] A working point of a cell or battery may be defined by the
electric current that is being drawn from the cell or battery, and
the cell's or battery's temperature. Typically, low currents result
in higher cell or battery voltage, but also in increased corrosion,
and therefore decreased columbic efficiency. Lower temperatures
result in lower voltage, but also result in reduced corrosion, and
therefore increased columbic efficiency. Therefore, there is a
tradeoff between higher voltage and higher columbic efficiency,
which essentially leads to the total energetic efficiency of the
cell or battery.
[0043] At a given moment, for a given discharge power, an optimal
working point of a cell or battery may be determined by the cell's
or battery's properties, and by the "age" of the electrolyte. An
age of an electrolyte as referred to is the amount of metal (e.g.,
aluminum, zinc, etc.) that is dissolved in the electrolyte. In some
cases, an age of an electrolyte is calculated based on the
percentage or ratio of dissolved metal in the electrolyte.
[0044] An embodiment may determine a current or instantaneous rate
at which metal is dissolving. For example, in an embodiment,
release of Hydrogen from an electrolyte is continuously measured by
a sensor and a controller uses Hydrogen release level or rate to
determine a rate at which metal from an anode is dissolving into
the electrolyte. For example, based on equation (2) above, a
controller uses the rate by which Hydrogen is released in a battery
to calculate the rate by which metal is dissolving in the
electrolyte. Accordingly, the rate by which an electrolyte is aging
is calculated by a controller. By continuously monitoring an aging
of an electrolyte, a controller can readily determine an age of an
electrolyte at any given point in time. As further described
herein, a system may cause a battery to operate such that the rate
by which Hydrogen is released, the rate by which an anode is
consumed and/or the rate by which the electrolyte in a battery is
aging are kept at a minimum or at any desirable rate or level.
[0045] Working at an optimal point (e.g., defined by drawn current,
and temperature) may be reflected in the cell's or battery's
voltage. For example, a desirable voltage in a range of 1v to 1.25v
may be maintained by an embodiment by controlling working
parameters as described herein. It will be understood that, where
applicable, any discussion of a cell is relevant to a battery that
includes one or more cells. For example, a discussion of energy
utilization of a cell is relevant to a plurality of cells in a
battery and is thus to be understood as a discussion of energy
utilization of a battery. Likewise, a discussion of heating or
cooling an electrolyte or cell is to be understood as a discussion
of heating and/or cooling a plurality of cells in a battery.
Accordingly, and for the sake of simplicity and clarity, cells may
be referred to herein when a battery is relevant and vice
versa.
[0046] Reference is made to FIG. 1, which graphically depicts
parameters that affect the energetic utilization of a metal-air
cell or battery and the interdependencies between such parameters.
As discussed, parameters such as anode composition, cathode
composition, cathode structure, geometrical design and the like
(collectively referred to herein as "design parameters") typically
effect or influence the energetic utilization of a cell or battery.
Such parameters are omitted from FIG. 1. As described herein, an
embodiment may measure, evaluate and compensate for changes in
design parameters of a battery.
[0047] To further describe the relations shown in FIG. 1, increased
electrolyte age (for example, in the range of 0 to 200 gram of
aluminum per liter of electrolyte) causes lower voltage but also
causes lower corrosion rate, and therefore may increase or decrease
the energetic utilization, depending on the specific working
conditions. Increased current (typically 0 to 400 milliampere (mA)
per square centimeter (cm.sup.2) of cathode) causes lower voltage,
but also causes reduced corrosion, and therefore may also increase
or decrease the energetic utilization. Increased temperature
(typically 0 to 90 degrees Celsius (.degree. C.)) increases the
voltage, but also increases corrosion, and therefore may also
increase or decrease the overall energetic utilization.
[0048] FIG. 1 shows the inter-relations between working parameters.
By controlling some of the parameters shown in FIG. 1 (e.g.,
current draw, voltage, temperature, corrosion rate, circulation
rate and electrolyte age) the parameters through which a required
result is achieved may be controlled. For example, to control
corrosion rate, a system controls a working temperature of a
battery. For example, corrosion rate may be decreased by decreasing
the temperature of a battery as described herein. In one
embodiment, a system controls one or more of: a current draw, a
temperature, a corrosion rate and an electrolyte age of a battery
such that, with respect to a metal-air battery, at least one of: a
desired energetic utilization, an instant power draw, a specific
voltage or a utilization profile are achieved and/or
maintained.
[0049] For example, in a typical battery, when a constant power
draw (in the form of a product of voltage and current denoted by
P=VI) is required, maximal utilization may be achieved by keeping
the cells' voltage V in the range of 1-1.25 volts, and setting the
current I that will yield the required power P according to this
voltage. In one embodiment, during operation and as the age of the
electrolyte increases, a controller included in a system causes a
heat exchanger to increase, in a controlled manner, the temperature
of the electrolyte or battery (e.g., by heating the electrolyte
and/or changing circulation rate of the electrolyte) such that the
voltage and the corrosion rate are maintained at a predefined or
suitable range. The corrosion rate may also be determined according
to the rate of hydrogen release from the battery. Consequently, a
momentary utilization ratio of the battery may be determined by
calculating the value utilization ratio=(1-corrosion rate) x cell
voltage/the theoretical voltage of the cell's reaction (For
example, for aluminum, the theoretical voltage is 2.71v, as shown
in equation (1), and for zinc the theoretical voltage is 1.65v). At
any given moment, a controller may change the temperature of the
battery (e.g., by activating or controlling a heat exchanger) and
the power draw from the battery (e.g., by controlling a current
regulator), such that a value of a utilization ratio is
maximized
[0050] Accordingly, the current invention enables increasing the
energetic utilization of a metal anode and an electrolyte in a
metal-air battery by controlling operational parameters. For
example, an embodiment controls parameters such as a working
temperature of a battery, an amount or magnitude of current drawn
from a battery, the voltages supplied by a battery, an age of an
electrolyte in a battery etc.
[0051] The system may control the working point of a metal-air
battery by controlling the working temperature. The system may
control the working point of a metal-air battery by controlling the
current drawn from the battery. Consequently, the voltage of the
battery is also determined or controlled. The system may consist of
a controller, a heat exchanger, a current regulator, and various
sensors such as a voltage sensors, a PH sensor, a conductance
sensor, a density sensor, a turbidity sensor, a Hydrogen sensor,
etc. The system may be adapted to control cell's or battery's
temperature by means of the heat exchanger, and may control the
current drawn from a cell or battery by means of the a current
regulator.
[0052] A system may determine the age of the electrolyte in one or
more of the following manners: monitoring and summing the metal
anode consumption, calculating the metal anode consumption,
measuring or calculating corrosion rate based on Hydrogen release,
measuring electrolyte conductivity, measuring electrolyte PH level,
measuring electrolyte density, measuring electrolyte turbidity,
measuring electrolyte viscosity etc.
[0053] As referred to herein, a discharge profile is characterized
or defined by the discharge current and voltage vs. the amount of
metal (e.g., aluminum, zinc any other metal suitable for metal air
batteries) dissolved into the electrolyte. A cell or battery may be
tested under various conditions in order to determine the cell's or
battery's capacity or behavior under various loads and conditions.
For example, a manufacturer of a battery may provide parameters,
values or graphs that characterize a battery and its expected
performance. An embodiment may define a discharge profile for a
battery such that the discharge profile matches a desired
performance. For example, on certain circumstances, a discharge
profile that leads to maximal energetic utilization may be
required, and on other circumstances, a profile that leads to lower
energetic utilization, but gives higher power, may be
preferred.
[0054] Data characterizing a battery may be provided to a
controller and used, the controller when controlling operation of a
metal-air battery. For example, if data provided by a manufacturer
indicates an optimal temperature for a battery then a controller
may cause the battery to operate in the optimal temperature. For
example, in one case, a controller continuously monitors and
adjusts working parameters of a battery such that a selected
discharge profile is executed. In another embodiment, a system
continuously monitors and adjusts working parameters of a battery
such that a required utilization ratio is maintained. In yet
another example, a system continuously monitors and adjusts working
parameters of a battery such that a required power is supplied,
while utilization ratio is maintained.
[0055] Reference is made to FIG. 2, a high level block diagram of
an exemplary system 200 according to embodiments of the present
invention. As shown in FIG. 2, a system may include a metal-air
battery 201 that is supplying energy to a load 203. For example,
the load may be an electric motor in a vehicle, light bulbs, or any
other electric power consuming entity. It will be understood that
embodiments of the invention are not limited to a specific load to
which electric energy is provided and any load may be used without
departing from the scope of the invention. For example, a vehicle
as referred to herein may be an electric car, a toy, a boat or a
plane of any size. A vehicle may be a manned or unmanned
vehicle.
[0056] As shown, battery 201 may include a metal-air cell (for
example, an aluminum-air cell) 202. For the sake of simplicity and
clarity, only one metal-air cell 202 is shown in battery 201,
however, it will be understood that any suitable number of cells
202 may be used according to embodiments of the invention. For
example, the number of cells may be chosen based on a desired
voltage to be provided by battery 201. It will be understood that
discussion of cell 202 herein is applicable to any number of cells
202 in a battery 201. For example, parameters measured for cell 202
may be measured for a plurality of cells, parameters set or
controlled for cell 202 (e.g., voltage, current draw, heat,
circulation etc.) may be set for a plurality of cells 202 in
battery 201.
[0057] As shown, a system may include a heat exchanger 205 that may
cool or heat a battery, cells or electrolyte included in battery
201. For the sake of clarity, electrolyte included in battery 201
is not shown, however, it will be understood that any space in
battery 201 or cell 202 may be filled with electrolyte. For
example, in an embodiment, heat exchanger 205 is placed in a
chamber through which electrolyte flows. Accordingly, a system may
heat or cool the electrolyte in a battery thus heat or cool a
battery. The electrolyte may flow through cell 202 thus cooling or
heating cell 202. In an embodiment, controller 219 controls
operation of heat exchanger. For example, controller 219 receives a
temperature measurement from temperature sensor 208 and controls
heat exchanger 205 such that a desired temperature of an
electrolyte in battery 201 (and consequently, temperature of
battery 201) is achieved and/or maintained.
[0058] In an embodiment, by controlling switches valves and the
like (not shown), controller 219 may cause heat exchanger 205 to
heat or cool cell 202 by causing cooled or heated electrolyte to
flow through cell 202. In other embodiments, heating or cooling may
be done using a fan, an electric element, a radiator, a fan
external to battery 201 and the like. Controller 219 may control
any heating or cooling device, system or component that may be
internal or external to battery 201. For example, a fan and heating
element component may be placed outside battery 201 and may be
controlled by controller 219 such that it cools or heats battery
201 or cell 202. In another embodiment, an electric heating element
controlled by controller 219 may be placed in battery 201 such that
it can heat electrolyte in battery 201.
[0059] For the sake of clarity, the electrolyte included in system
200 is not shown. However, it will be understood that electrolyte
may be present inside battery 201, inside cell 202 and in
electrolyte tank 206 and may be made to reach, or flow to or
through any part of system 200 as required, e.g., using tubes,
orifices and the like.
[0060] As shown, system 200 may include an electrolyte tank 206 and
a pump 207. Pump 207 may circulate electrolyte through system 200.
In an embodiment, controller 219 controls operation of pump 207.
For example, controller 219 causes pump 207 to transfer electrolyte
from electrolyte tank 206 to cells in battery 201 or cause pump 207
to transfer electrolyte from battery 201 to electrolyte tank 206.
Controller 219 may control the capacity of pump 207, e.g.,
configure pump 207 to circulate, between electrolyte tank 206 and
battery 201, a first volume of electrolyte per second, during a
first period of time and configure pump 207 to circulate a second
volume of electrolyte per second during a second period of time.
Accordingly, controller 219 controls the rate of circulation of
electrolyte through system 200.
[0061] In another embodiment, in order to remove deposits of matter
from a cathode or anode in cell 202, controller 219 controls pump
207 and heat exchanger 205 such that a desired combination of
circulation and temperature is achieved. For example, to remove
deposits of matter from an aluminum anode in cell 202, controller
219 may first cause heat exchanger 205 to heat electrolyte in
electrolyte tank 206 or electrolyte in battery 201 and, when the
proper or desired temperature of the electrolyte is reached,
controller 219 activates pump 207 thus causing warm or hot
electrolyte to circulate through cell 202 and efficiently remove
deposits of matter from the anode in cell 202. It will be noted
that heat exchanger 205 may be placed in battery 201 as shown, in
electrolyte tank 206 or two heat exchangers may be used, installed
in both battery 201 and electrolyte tank 206.
[0062] In one embodiment, prior to activating or re-activating the
battery, controller 219 determines the age of electrolyte before
activating the battery (e.g., by pumping electrolyte into the
cells), controller 219 sets the temperature of the electrolyte to a
predefined value. For example, based on a profile or specification,
controller 219 sets the temperature of the battery such that an
optimal utilization of the electrolyte is achieved. For example,
controller 219 warms the electrolyte in tank 206 and only when the
electrolyte reaches a predefined temperature (e.g., as defined in a
profile and/or based on the age of the electrolyte) does controller
219 commands pump 207 to circulate electrolyte through battery 201
and/or cell 202.
[0063] For example, in one embodiment, in order to restart or
reactivate a battery, the operation of which was terminated or
stopped before the electrolyte was completely utilized, controller
219 controls pump 207 and heat exchanger 205 such that a desired
combination of circulation and temperature is achieved.
[0064] For example, to restart a battery that was stopped (e.g.,
disconnected from a load) at a time when the electrolyte was at a
temperature of 60 degrees Celsius (60.degree. C.), controller 219
first causes heat exchanger 205 to heat electrolyte in electrolyte
tank 206 and/or electrolyte in battery 201 and, when the
temperature of the electrolyte reaches 55-65 degrees Celsius
(55-65.degree. C.), controller 219 activates pump 207 thus causing
warm or hot electrolyte to circulate through cell 202, thus
restarting the battery with the correct temperature corresponding
to the age of the electrolyte.
[0065] As shown, system 200 may include a temperature sensor 208, a
voltage sensor 209, a current sensor 210, a flow rate sensor 211, a
pressure sensor 212, a conductivity sensor 213, a PH sensor 214, a
density sensor 215, a turbidity sensor 216, and a hydrogen sensor
217. It will be understood that some of the sensors shown included
in system 200 may be optional. For example, some embodiments may
not include all sensors shown. Likewise, embodiments of the
invention may include sensors not shown in FIG. 2 that may be used
to monitor aspects of battery 201. For the sake of clarity, a
single sensor of each type is shown but it will be understood that
a plurality of sensors of the same type may be included in system
200. For example, a plurality of voltage sensors 209 may be
connected to a plurality of cells 202 in a battery 201.
[0066] In an embodiment, temperature sensor 208, voltage sensor
209, current sensor 210, flow rate sensor 211, pressure sensor 212,
conductivity sensor 213, PH sensor 214, density sensor 215,
turbidity sensor 216 and hydrogen sensor 217 are operatively
connected to controller 219 such that signals or output generated
by these sensors are provided to controller 219. Using parameters
measured, sensed or monitored by the sensors, controller 219 may
determine a state of battery 201 and may command components in
system 200 such that a desired operational or other state of
battery 201 is reached and/or maintained.
[0067] The above mentioned sensors may be any suitable sensors as
known in the art. It will be understood that embodiments of the
invention are not limited by the type, nature, or way of operation
of any of the described sensors. Various other sensors may be
included in a system as required. For example, in order to
determine an age of an electrolyte in a battery, a viscosity sensor
may be added and controller 219 may use data related to a viscosity
or thickness of the electrolyte in order to determine its age or
quality.
[0068] In an embodiment, controller 219 controls the temperature of
battery 201 by activating heat exchanger 205 and monitoring the
temperature of battery 201 based on input received from temperature
sensor 208, and, when a desired temperature is achieved, controller
219 stops operation of heat exchanger 205. In another example,
using input from a thermometer that measures ambient temperature
(e.g., one installed in a car), controller 219 may cause or command
heat exchanger 205 to provide a constant heat such that the
temperature of battery 201 is maintained at a predefined or
desirable temperature range.
[0069] Controller 219 may be connected to any sensor or unit, e.g.,
units external to system 200. For example, when installed in a
vehicle, controller 219 may be connected to sensors or units that
provide data related to a speed at which the vehicle is traveling,
an altitude, a temperature outside the vehicle, engine temperature
and the like. Any information collected or obtained by controller
219 from any applicable unit, component or sub-system in a vehicle
may be used by controller, where applicable, to control an
operation of a battery as described herein. For example, the above
mentioned information my allow controller 219 to determine how much
power a vehicle is expected to require from its electric energy
source, and adjust working parameters of the metal-air battery to
deliver required power while maintaining its efficiency.
[0070] In one embodiment, controller 219 controls the amount of
energy that is drawn from, or supplied by, battery 201 by
controlling current regulator 204. For example, if, based on a
profile, a constraint, a condition or a configuration parameter,
controller 219 determines that current drawn from battery 201 is to
be limited, then controller 219 uses current regulator 204 in order
to limit electric current being drawn from battery 201. For
example, current regulator 204 may be a variable and controllable
resistor or a DC to DC convertor controlled by controller 219 such
that current flowing from battery 201 to load 203 is kept at a
desired level or magnitude.
[0071] In one embodiment, data related to attributes,
characteristics and/or properties of battery 201 are provided by a
manufacturer of battery 201 and may be used. For example, capacity,
power and voltage (and interdependencies between these parameters)
of battery 201 may be obtained from the manufacturer, and a profile
that is best used with a specific battery 201 may be generated
using such attributes.
[0072] In one embodiment, a battery or cell may be tested prior to
being operated as described herein. For example, each cell in
battery 201 may be tested in various working conditions (e.g., with
each of a current, voltage and/or temperature held at various
values), in order to determine a discharge curves of the cell.
Various curves may be tested and analyzed to determine the
performance features that may be realized. A number of
charge/discharge curves may be selected for use. For example, a
first selected curve may be energetically optimal and a second
selected curve may be power optimal. Controller 219 may be provided
with selected curves or discharge profiles for a battery and may
use provided curves in order to control operation of battery 201.
For example, controller 201 controls the temperature of battery 201
and/or current being drawn from battery 201 as described herein
such that a selected curve or profile is maintained.
[0073] System 200 may control operation of a battery such that a
predefined operational profile is executed or maintained. For
example, a discharge profile characterized by the discharge current
and voltage with respect to the amount of metal dissolved into the
electrolyte may be achieved. For example, using data received from
one or more sensors, controller 219 determines the age of an
electrolyte in battery 201. For example, by measuring density, PH,
hydrogen and/or turbidity of an electrolyte with respect to time
and usage (e.g., in a lab), the electrolyte is profiled such that
for specific levels of density, PH, hydrogen and/or turbidity and
based on an electrolyte profile, the age of the electrolyte may be
determined Accordingly, in one embodiment, provided with an
electrolyte profile and data from attached sensors, controller 201
determines the age of the electrolyte.
[0074] In one embodiment, a discharge profile defines the discharge
current and voltage. To cause battery 201 to operate according to a
specific discharge profile, controller 219 uses current regulator
204 to set the current being drawn from battery 201 to the value
defined in the discharge profile. In an embodiment, to cause
battery 201 to operate at the voltage level defined by a discharge
profile, controller uses heat exchanger 205. As described, voltage
provided by battery 201 may be raised by raising the temperature of
battery 201 and cooling battery 201 will cause a decrease in
provided voltage. Accordingly, in one embodiment, controller 219
causes heat exchanger 205 to heat or cool battery 201 so that the
voltage defined in the discharge profile is achieved.
[0075] Controller 219 may monitor all aspects related to a profile
and concurrently or simultaneously control a plurality of units
such that each of a plurality of characteristics may be maintained.
For example, while monitoring the voltage of battery 201 and
causing heat exchanger 205 to heat battery 201 in order to raise
the voltage controller 219 may monitor the current being drawn
(using current sensor 210) and if, with rising temperature, the
current drawn is increased above the current defined in the
discharge profile, controller 219 may cause current regulator 204
to limit current drawn from battery 201. Accordingly, controller
219 may simultaneously monitor and control a plurality of
operational characteristics of battery 201. In another embodiment,
controller 219 may iterate over a plurality of parameters or
characteristics, setting each one in turn and repeating the process
until the discharge or other profile is reached and maintained for
a period of time or until the state of the system changes.
[0076] For example, first, controller determines the age of the
electrolyte. Next, by controlling current regulator 204, controller
219 sets the current drawn from battery 201, then, controller 219
uses heat exchanger 205 to raise or lower the supplied voltage,
controller 219 then repeats the steps of determining the
electrolyte age, setting the current and setting the voltage. In
one embodiment, controller 219 repeats the steps of determining the
electrolyte age, setting the current and setting the voltage until
a predefined discharge profile is reached. In another embodiment,
controller 219 repeats the steps of determining the electrolyte
age, setting the current and setting the voltage continuously such
that adherence to a discharge (or other) profile is continuously
maintained.
[0077] In another example, a specific relation between the amount
of electric energy that is extracted from each Kg of metal and the
total energy in each Kg of metal in battery 201 is maintained, this
relation is referred to herein as a utilization ratio. In an
embodiment, controller 219 monitors at least one of the voltage and
current supplied by battery 201 (e.g., as described herein) to
determine a current or momentary energetic utilization. In an
embodiment, to achieve a desired utilization ratio, controller 219
determines the age of the electrolyte in battery 201, e.g., as
described herein. By controlling heat exchanger 205, controller 219
then sets the voltage supplied by battery 201, e.g., as described
herein.
[0078] In one embodiment, controller 219 examines data received
from hydrogen sensor 217 and, using heat exchanger 205, causes an
increase or decrease of the temperature of battery 201 such that
the hydrogen evolution or release corresponds to a desired rate,
e.g., as defined in a profile. As described, the level of hydrogen
in the electrolyte may be indicative of the rate at which metal is
consumed without providing electricity. Accordingly, in order to
maintain a specific relation between energy and consumed metal, a
system may monitor hydrogen levels in the electrolyte and adjust
working parameters such that the relation is maintained. The
operations performed to achieve a predefined ratio of energy to
metal consumption may be performed sequentially or concurrently.
The operations performed to achieve a predefined ratio of energy to
metal consumption may be repeated continuously (e.g., in a loop)
such that the ratio is continuously maintained.
[0079] System 200 may cause battery 201 to operate according to a
mix of profiles or according to any combination of constraints or
characteristics. In an exemplary embodiment or case, system 200
causes battery 201 to operate such that a specific, required or
predefined power is supplied and a specific or defined utilization
ratio is maintained. For example, controller 219 sets the current
drawn to a first level (e.g., using current regulator 204). Next,
controller 219 sets the operating voltage such that the required
power is achieved. As known in the art, a number of combinations of
current and voltage values or levels may be used to achieve a
specific power. In one embodiment, to achieve both a specific power
and a specific utilization ratio, controller 219 monitors the
hydrogen evolution rate and increase or decrease the temperature of
battery 201 such that the hydrogen evolution rate corresponds to
the rate defined by the utilization ratio. Accordingly, in order to
achieve both a predefined power and a specific utilization ratio,
controller may adjust any one of a current drawn from a battery, a
voltage provided by the battery and an operating temperature of the
battery. In one embodiment, controller 219 continuously monitors
the age of an electrolyte in battery 201, power drawn from battery
201 and the temperature of battery 201 and, taking into account the
age of the electrolyte, continuously adjusts power drawn and
temperature such that operational characteristics as defined are
maintained.
[0080] Controller 219 may be connected to any applicable unit or
component and may adjust working parameters of battery 201
according to any applicable conditions. For example, when system
200 is installed in a vehicle, speed of movement of the vehicle,
controls from a driver, engine operational state, supplementary
power sources and the like may all be taken into account. For
example, controller 219 may receive input form sensors inside the
car, the communication line in the car, sensors mounted on the
engine or motor of the car, and sensors attached to an auxiliary
source.
[0081] Controller 219 may use input from a driver of a car in which
system 200 is installed and input from an engine or other
components in the car and input from an auxiliary battery in order
to set working characteristics or profiles of battery 201.
Controller 219 may dynamically cause battery 201 to operate
according to a current or instantaneous condition or
requirement.
[0082] For example, when a driver steps on the acceleration pedal
of an electrically operated car, controller 219 may switch from a
utilization profile to a power surge profile where the power surge
profile may not be best in terms of energetic utilization of
battery 201 but may be best in terms of power. In another case,
determining an auxiliary battery (e.g., electric power source 320
described below with reference to FIG. 3) is fully charged, and, in
order to maintain energetic utilization as defined in a profile,
controller 219 may decrease power drawn from battery 201 and allow
the auxiliary battery to provide power.
[0083] In an embodiment, controller 219 automatically adjusts
working parameters of battery 201 such that an optimal usage of
battery 201 is achieved. For example, in one embodiment, by
receiving signals from a tachometer and/or a speedometer in an
electric car, controller 219 may deduce that the car is stationary
or that low power is required. In such case, controller 219 may
switch to an operational mode that best preserves the life of
battery 201, e.g., cause battery 201 to operate according to a low
power and high utilization profile as described.
[0084] Reference is made to FIG. 3, an exemplary system 300
according to embodiments of the invention. As shown, system 300 may
include a system 200 as described herein, including a metal-air
battery 201. For the sake of simplicity and clarity, other
components of system 200 are not shown in FIG. 3. As shown, system
300 may include a controller 310 that may be similar to controller
219. In an embodiment, controller 219 may be replaced by controller
310. When replacing controller 219, controller 310 may be connected
to any sensor connected to controller 219 as described herein. In
other embodiments, e.g., when both controllers 219 and 310 are
included in system 300, controller 310 may communicate with
controller 219 and receive any data received or obtained by
controller 219. Accordingly, it will be understood that any
operations described herein with respect to controller 219 may be
performed by controller 310.
[0085] In one embodiment, controllers 219 and 310 include a
processor and memory. A non-transitory memory connected to
controller 310 may store a set of instructions that when executed
by controller 310 cause controller 310 to perform operations and
methods described herein. In an embodiment, a non-transitory memory
unit connected to controller 310 stores discharge or other profiles
described herein.
[0086] As further shown, system 300 may include a plurality of
power sources 320 and 321. For example, power source 320 may be a
rechargeable battery or a super capacitor as known in the art and
power source 321 may be a solar power source. For the sake of
simplicity, other than metal-air battery 201, only two power
sources 320 and 321 are shown. However, it will be understood that
any number of power sources may be included in system 300, may be
connected to current regulation and switching unit 325 and may be
controlled by controller 310. As shown, system 310 may include a
current regulation and switching unit (CRSU) 325. As shown, CRSU
325 may include a current regulator 326 and a switching component
327.
[0087] For example, current regulator 326 may be similar to current
regulator 204 but may be configured to regulate current flow
from/to any power source or load connected to CRSU 325. Current
regulator 326 may include a plurality of current regulators and
may, accordingly, regulate currents in multiple paths. For example,
in one embodiment, current regulator 326 is adapted to set
different current limits for different paths. For example, in one
embodiment, based on control from controller 310, current regulator
326 sets a first limit on current flowing from system 200 to load
330, sets a second limit on current flowing from system electric
power source 320 to load 330 and further sets a third limit on
current flowing from power source 321 to power source 320.
[0088] Switching component 327 may be a component configured to
electrically connect and/or disconnect any component or unit
connected to CRSU 325. For example, switching component 327 may
establish a first electric connection between power source 320 and
load 330 and further establish a second connection between system
200 and power source 320. Accordingly, CRSU 325 may route electric
current from/to any connected component or unit and may further
regulate the current flows to/from any connected component or
unit.
[0089] For example, CRSU 325 may connect electric power source 321
to load 330 and, at the same time, connect system 200 to electric
power source 320. Switching component 327 may include a plurality
of electrically operated switches and, using such switches,
switching component 327 may enable electrically
connecting/disconnecting any attached electric power source
(including system 200) to/from any other electric power source.
Similarly, switching component 327 may electrically
connect/disconnect any attached electric power source to/from load
330. Accordingly, using power regulator 326, CRSU 325 may enable
controlling the current being drawn from any one of the electric
power sources connected thereto and, in addition, using switching
component 327, CRSU 325 may direct electric current from any
connected power source to any connected power source or to load
330. It will be understood that a plurality of loads may be
connected to CRSU 325.
[0090] In one embodiment, based on a control signal from controller
310, CRSU 325 may cause system 200 to provide a predefined or
specific power to load 330 and further cause electric power sources
320 and 321 to provide any additional power required. In another
case, if power required by load 330 is less than can be provided by
system 200, then, based on a control signal from controller 310,
CRSU 325 may cause system 200 to provide electric power to one or
both of power sources 320 and 321. For example, if power source 320
is a rechargeable battery then, if the electric power or current
that can be provided by system 200 is more than required by load
330, than, based on a control signal from controller 310, CRSU 325
may cause system 200 to provide electric power to power source 320
such that system 200 charges power source 320.
[0091] Although not shown, any relevant sensors may be installed on
any one of power sources 320 and 321 and load 330 and installed
sensors may be connected to controller 310. For example, sensors
similar to those shown in FIG. 2, e.g., a voltmeter, may be
installed in power sources 320 and 321. Accordingly, controller 310
may be aware of a state or condition of components in system 300
and may control CRSU 325 based on a state of any one of system 200,
load 330 and power sources 320 and 321. For example, if power
source 321 is a solar power source and power source 320 is a
rechargeable battery, then, based on a control signal from
controller 310, CRSU 325 may cause power source 321 to charge power
source 320 or provide power to load 330. In another time or case,
based on a control signal from controller 310, CRSU 325 may cause
power source 321 to both charge power source 320 and provide power
to load 330.
[0092] In one embodiment, controller 310 periodically or
continuously monitors, determines and/or calculates working
conditions of battery 201. For example, controller 310 monitors,
based on input from sensors described herein, a temperature of
battery 201, current drawn from battery 201 and voltage of battery
201. In one embodiment, controller 310 periodically or continuously
monitors, determines and/or calculates the age of an electrolyte in
battery 201 as described herein. In one embodiment, controller 310
periodically or continuously monitors, determines and/or calculates
an energetic utilization of battery 201.
[0093] For example, using data from hydrogen sensor 217, controller
310 determines corrosion rate as described. In another embodiment,
controller 310 uses a current density value. A current density as
known in the art is a measure of electric current per volume or per
cross-sectional area. For example, the current density of a metal
in metal-air battery 201 may be provided to controller 310, e.g.,
store in a memory accessible to controller 310. By considering the
current density and temperature of battery 201 and the age of the
electrolyte in battery 201, controller 310 determines the energetic
utilization of battery 201. For example, controller 310 uses a
lookup table (e.g., provided by b manufacturer of battery 201) in
order to determine the energetic utilization based on an age of the
electrolyte, a current density and/or temperature of battery
201.
[0094] In one embodiment, to achieve a desired or optimal energetic
utilization, controller 310 observes the voltage of battery 201
(using voltage sensor 209) and tunes a system to the voltage that
produces the right or optimal efficiency in terms or energetic
utilization. For example, using current regulator 326, controller
sets the current drawn from battery 201 to a constant level or rate
and then uses heat exchanger 205 to set the temperature of battery
201 such that the a desired voltage provided by battery 201 is
achieved. As described herein, in one embodiment, the voltage
provided by battery 201 is controlled by controlling the
temperature of battery 201. Accordingly, controller 310 controls
the current drawn from battery 201 and the voltage of battery 201
such that a desired energetic utilization is achieved and
maintained.
[0095] In one embodiment, controller 310 causes battery 201 to
operate such that an optimal utilization is achieved. For example,
after determining conditions of battery 201, such as temperature,
current drawn and voltage and further calculating the momentary
energetic utilization of battery 201, controller 310 adjusts
working parameters or conditions of battery 201 as described. For
example, controller 310 increases or decreases current drawn from
battery 201, increases or decreases the voltage or temperature of
battery 201 as described herein such that a desired working point
is reached
[0096] For example, consider an aluminum-air cell with fresh
electrolyte at a temperature of 50.degree. C., running at a current
density of 200 ma/cm.sup.2, a voltage of 1.1V, and a corrosion rate
of 10%. A voltage efficiency parameter is calculated by dividing a
current voltage of the cell by the theoretical voltage that can be
provided by the cell, e.g., 1.1/2.7 for Aluminum.
[0097] The momentary energetic utilization rate is calculated by
controller 310 as the product of the "columbic efficiency" and
"voltage efficiency". In this example, the momentary energetic
utilization is 0.366 according to: 0.9.times.(1.1V/2.7V)=0.366. To
increase the energetic utilization, controller 310 increases the
current density to 250 ma/cm.sup.2 (by controlling current
regulator 326) and therefore, the corrosion rate drops to 1%, and
the voltage drops to 1.05v. Accordingly, the energetic efficiency
is increased from 0.366 to to 0.99.times.(1.05V/2.7V)=0.385.
[0098] Reference is made to FIGS. 6A and 6B that illustrate a
behavior of a temperature controlled metal-air battery. FIGS. 6A
and 6B illustrate an increase in energetic efficiency according to
embodiments of the invention. In both graphs shown by FIGS. 6A and
6B, the current drawn from a battery is constant throughout the
discharge. As shown by FIG. 6A, when the temperature is constant,
the battery voltage continuously drops with the age of electrolyte
(expressed in Watt Hour per liter of electrolyte (Wh/liter)), and,
as shown, at 310 Wh/liter the electrolyte is exhausted. As shown by
FIG. 6B, when the temperature of the electrolyte is gradually
increased, and a voltage of 1.2v is maintained through the
discharge. The heated electrolyte is only exhausted after drawing
500 Wh/liter of electrolyte. Accordingly, by controlling the
temperature of a battery, a system according to embodiments of the
invention dramatically increases the utilization of electrolyte in
a metal-air battery.
[0099] In one embodiment, load 330 is an electric vehicle (EV) and
electric power source 320 is a rechargeable battery. Reference is
additionally made to FIG. 4, which shows an exemplary configuration
that may be assumed or achieved by system 300. In one embodiment,
the configuration shown in FIG. 4 is achieved by configuring CRSU
325. For example, controller 310 causes CRSU 325 to connect system
200 to rechargeable device 410 (that may be electric power source
320) through current regulator 326 and further configures CRSU 325
to connect rechargeable device 410 to EV 415 as shown. In another
embodiment, permanent or fixed connections may used to configure a
system as shown by FIG. 4.
[0100] In one embodiment, when used in an electric vehicle 415, a
metal-air battery 201 is connected to a rechargeable device 410
which in turn is connected to the vehicles drive system. In this
embodiment, controller 310 causes energy to be drawn from battery
201 at a constant rate. In an embodiment, the constant rate is
determined by calculating an average energy level or rate consumed
by EV 415. For example, controller 310 periodically or continuously
measures current provided to EV 415 by both battery 201 and
rechargeable device 410, and periodically or continuously
calculates and average energy required to operate EV 415. In one
embodiment, controller 310 causes battery 201 to provide the
calculated average current or energy and uses rechargeable device
410 as a buffer that supplies additional power when EV 415 requires
more than the average power, and absorbs power when EV 415 requires
less than the average power. For example, battery 201 provides
power for a normal drive but when EV accelerates and more than the
average power is needed, rechargeable device 410 provides the
additional required power. In one embodiment, when electric energy
is generated by EV 415 rather than consumed, e.g., by regenerative
breaking as known in the art, the electric energy generated by EV
415 is used to charge rechargeable device 410.
[0101] As shown by FIG. 4, in an exemplary configuration, system
200 is connected to a rechargeable device or battery 410 through a
current regulator (e.g., current regulator 326). In one embodiment,
the rechargeable device 410 is connected to EV 415 thus providing
power to an electric motor in EV 415 as well as to any other
electric loads or circuits in EV 415. As shown, EV 415 may include
a controller 420. For example, controller 420 may be an onboard
computing device installed in a vehicle as known in the art.
Controller 410 may be operatively connected to controller 310 (not
shown in FIG. 4 for clarity). Accordingly, any data obtained or
generated by controller 420 may be provided to, and used by,
controller 310.
[0102] In one embodiment, the capacity of rechargeable device 410
is such that it is capable of supplying a power surge that may be
required by EV 415, e.g., for accelerating, hill climbing, or any
other driving condition that require a short burst of high power.
Rechargeable device 410 may or may not be recharged from an
electricity grid, e.g., in a home. Due to the nature of a metal-air
battery, it is expected, but not required, that the capacity of the
metal-air battery 210 is significantly larger than the capacity of
rechargeable device 410. The metal-air battery 210 can accordingly
serve as a range extender for EV 415, and, accordingly, battery 201
or system 200 may be referred to herein as a range extender.
[0103] In order for a range extender to extend the driving distance
of EV 415, the range extender (e.g., system 200 or a meta-air
battery 201) may not be required to supply a momentary power
requirement of EV 415, but rather, supply an average power
consumption of EV 415. Accordingly, system 200 or battery 201
(referred to herein as the range extender) has to be utilized in
different ways in order to accommodate for requirements of each
trip. Such requirements may include maximal energetic efficiency,
specific power requirement, a changing power profile, or any
combination of the above. Controller 310 may configure the range
extender (e.g., system 200) for any condition or requirement.
[0104] In one embodiment, controller 310 may monitor the state of
charge of the rechargeable device 410, as well as other driving
parameters such as driving destination, road conditions, vehicle
power consumption statistics, a driving style, etc. For example,
controller 310 may be connected to controller 420 installed in the
EV 415 and thus receive any information needed. As described, based
on data supplied by sensors, controller 310 may be aware of the
state of the range extender (system 200 and/or metal-air battery
201) and the state of rechargeable device 410. For example,
controller 310 may determine the capacity of the battery 201 and
the capacity of rechargeable device 410 (e.g., system 200 and power
source 320). Accordingly, controller 310 may choose and set any
working points, charge level, power draw and/or other parameters of
both system 200 (when used as a range extender) and rechargeable
device 410.
[0105] For example, controller 310 may maintain a minimal state of
charge of rechargeable device 410 by controlling the current being
drawn from system 200. For example, if controller 310 determines
that capacity of rechargeable device 410 is below a threshold,
controller 310 may cause system 200 to charge the rechargeable
device 410 (e.g., by connecting system 200 to rechargeable device
410 through CRSU 325).
[0106] In one embodiment, it may be desirable to control usage of a
rechargeable battery or device. For example, in order to extend the
life of rechargeable device 410, it may be desirable to limit its
usage. In one embodiment, in order to limit usage of rechargeable
device 410, controller 310 draws power from metal-air battery 201
at all times, and thus EV 415 draws power from a rechargeable
battery (e.g., rechargeable device 410) only if the power from the
metal-air battery 201 is insufficient for its power requirement. In
other embodiments, e.g., if metal-air battery 201 is an expensive
resource and rechargeable device 410 is a cheap one, controller 310
may cause rechargeable device 410 to provide as much current as can
be drawn from it while keeping usage of metal-air battery 201 at a
minimum. Using current regulation and switching capabilities of
CRSU 325, controller 310 can discretely set power or current drawn
from each power source attached to CRSU 325.
[0107] Accordingly, system 300 enables discretely setting the
amount of electric power provided to load 330 or EV 415 by each
power source in the system. In yet another embodiment, e.g., if,
due to power cuts or electric power outage, charging rechargeable
device 410 is impossible, controller 310 disconnects rechargeable
device 410 from EV 415 and only reconnects rechargeable device 410
to EV 415 when metal-air battery 210 is unable to supply required
power. It will be understood that, using CRSU 325, controller 310
can configure a system such that metal-air battery 210 and
rechargeable device 410 each contribute a portion of the power
required by EV 415 as determined by controller 310. For example, in
one embodiment, controller 310 maintains the capacity of
rechargeable device 410 such that it can support a power surge
required by EV 415. Controller 310 may observe maximal state of
charge rechargeable device 410 to enable efficient regenerative
breaking or downhill energy regeneration, minimal usage of the
range extender before reaching grid power, etc.
[0108] In order to maintain configured or determined thresholds,
controller 310 may turn the range extender on or off at any time.
When activating the range extender (e.g., by connecting system 200
to load 330 using CRSU 325), controller 310 may control the range
extender (system 200) to supply nominal power for maximal energetic
efficiency, to deliver maximal power, or to deliver any other set
or predefined power.
[0109] A rechargeable buffer can be used as a buffer in more than
one way. For example, in one embodiment, the rechargeable device is
designed to have the energy capacity that is required for an EV's
daily average usage of energy. In each day, if the average amount
of energy is used, it may be taken solely from the rechargeable
device, which, in turn, can be recharged when connected to the grid
(an electric power socket in a home). If the daily energy
consumption is beyond the average, controller 310 can operate the
metal air battery 201 such that it delivers the additional energy
that is required beyond the available energy in the rechargeable
device.
[0110] Accordingly, an EV can be normally operated by charging the
buffer (e.g., a rechargeable battery) on a regular basis and using
the rechargeable battery for the daily, normal trips but, in cases
when a trip longer than the average is taken, the metal-air battery
is used, e.g., when the rechargeable battery is depleted or is
discharged to a preconfigured level. For example, when a
rechargeable battery is discharged down to a preconfigured level,
controller 310 activates the metal-air battery. Accordingly, a
system or electric vehicle according to embodiments of the
invention is designed such that the capacity of a rechargeable
device in the electric vehicle is designed to supply an average
daily energy consumption of the electric vehicle and a metal-air
battery in the electric vehicle is designed to supply energy in
excess of the average daily energy.
[0111] Reference is now made to FIG. 5, an exemplary flow according
to embodiments of the invention. As shown by block 510, a method or
flow may include selecting a profile characterizing an operation of
a battery. For example, in one embodiment, controller 219 or
controller 310 selects a profile that characterizes or defines an
operation of battery 201. As described, in one embodiment,
controller 219 or controller 310 selects a profile such that the
columbic efficiency of battery 201 is maximized For example, a
profile selected includes setting the temperature of battery 201
and circulation of electrolyte in battery 201 such that the
corrosion reaction as shown by equation (2) above is minimized In
another case, controller 219 or controller 310 selects a profile
such that the energetic utilization of metal in battery 201 is
maximized In yet another embodiment or case, controller 219 or
controller 310 selects a profile such that the electrolyte
utilization in battery 201 is maximized A profile may be a set of
values stored in a memory accessible to controller 219 and/or
controller 310. A plurality of profiles may be provided, e.g., by a
manufacturer of battery 201 and may be stored in a memory
accessible to controller 219 and/or controller 310. Accordingly,
controller 219 or controller 310 may select a profile from a
plurality of profiles.
[0112] Various parameters may be taken into account when selecting
a profile or when causing a battery to operate based on a profile.
For example, as described herein, release of hydrogen may indicate
corrosion rate or level. Accordingly, in one embodiment, controller
219 uses data received from hydrogen sensor 217 to determine the
level or rate hydrogen released by battery 201 and, adjusts
operational parameters of battery 201 such that the rate or level
of hydrogen release is kept within a predefined range. For example,
a profile may indicate a rate of hydrogen release and controller
219 increases, or decreases, power consumption from battery 201, or
adjusts a temperature of battery 201 such that hydrogen release
limits are observed.
[0113] As shown by block 515, a method or flow may include
controlling a current drawn from the battery according to the
profile. For example, using current regulator 326 controller 310
controls the current drawn from battery 201. As shown by block 520,
a method or flow may include controlling a voltage provided by the
battery according to the profile. For example, controller 219
controls the temperature of battery 201 and thus, as described,
increases or decreases the voltage provided by battery 201. As
shown by block 525, a method or flow may include controlling a
temperature of the battery. For example, by controlling heat
exchanger 205 controller 219 decreases or increases the temperature
of electrolyte in battery 201 thus decreases or increases the
temperature of battery 201.
[0114] As shown by block 530, a method or flow may include
controlling a circulation of electrolyte in the battery. For
example, controller 219 controls pump 207 thus controlling a
circulation of electrolyte through cells in battery 201. In one
embodiment, controlling operational parameters as shown by blocks
515, 520, 525 and 530 may be according to, or based on a
profile.
[0115] As shown by block 535, a method or flow may include
determining a power required by a load. For example, controller 310
determines a load based on information received from controller 420
in an EV 415. Determining a load may include predicting a load. For
example, controller 310 uses global positioning system (GPS) data
to predict a load. In another case, controller 310 uses a route
specification received from controller 410 to predict a load. In
one embodiment, controller 310 selects a profile based on a
predicted load. For example, if based on a travelled route,
controller 310 identifies that an up hill travel is expected then
controller 310 selects a profile where by the power provided by
battery 201 is maximized When determining that the power required
is low, e.g., based on revolutions per minute (RPM) of an electric
motor in EV 415, controller 310 selects a profile whereby the
corrosion rate in battery 201 is minimized Any data collected by
controller 420 in EV 415 may be used in order to select a profile
or otherwise set working parameters of battery 201 or system
200.
[0116] As shown by the arrow connecting blocks 535 and 510,
selecting a profile may be automatic and dynamic. For example,
determining that EV 415 is stationary based on data received from
controller 420, controller 219 or controller 310 selects a profile
such that low power is produced and corrosion rate is minimized
Next, determining EV 415 is in motion, controller 219 or controller
310 selects a profile such that power provided by battery 201 is
maximized
[0117] As shown by block 540, a method or flow may include causing
a battery to provide a first portion of the required power and
causing a secondary power source to provide a second portion of the
required power. For example, by controlling CRSU 325, controller
310 causes battery 201 to provide a predefined current to load 330
(that may be EV 415) and further causes electric source 320 to
provide additional current such that a demand for power by load 330
is satisfied. In one embodiment, when power is required, a power
regulator limits the power provided by battery 201 and the rest of
the required power is provided by a rechargeable battery that
serves as a buffer. Accordingly, a buffer is used for cases when a
demand for power peaks.
[0118] Unless explicitly stated, the method embodiments described
herein are not constrained to a particular order or sequence.
Additionally, some of the described method embodiments or elements
thereof can occur or be performed at the same point in time.
[0119] While certain features of the invention have been
illustrated and described herein, many modifications,
substitutions, changes, and equivalents may occur to those skilled
in the art. It is, therefore, to be understood that the appended
claims are intended to cover all such modifications and changes as
fall within the true spirit of the invention.
[0120] Various embodiments have been presented. Each of these
embodiments may of course include features from other embodiments
presented, and embodiments not specifically described may include
various features described herein.
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